Background Haemodialysis patients experience significant symptom burden and effects on health-related quality of life. Studies have shown increases in fluid overload, hospitalization and mortality immediately after the long interdialytic interval in thrice weekly in-centre haemodialysis patients, however the relationship between the dialytic interval and patient reported outcome measures (PROMs) has not been quantified and the extent to which dialysis day of PROM completion needs to be standardised is unknown. Methods Three times a week haemodialysis patients participating in a stepped wedge trial to increase patient participation in haemodialysis tasks completed PROMs (POS-S Renal symptom score and EQ-5D-5L) at recruitment, six, 12 and 18 months. Time from the long interdialytic interval, HD day of the week, and HD days vs non-HD days were included in mixed effects Linear Regression, estimating severity (none to overwhelming treated as 0 to 4) of 17 symptoms and EQ-5D-5L, adjusting for age, sex, time on HD, control versus intervention and Charlson Comorbidity Score. Results 517 patients completed 1659 YHS questionnaires that could be assigned HD day (510 on Mon/Tue/Sun, 549 on Wed/Thu/Tue, 308 on Fri/Sat/Thu and 269 on non-HD days). With the exception of restless legs and skin changes, there was no statistically significant change in symptom severity or EQ-5D-5L with increasing time from the long interdialytic interval. Patients who responded on non-HD days had higher severity of poor appetite, constipation, difficulty sleeping, poor mobility and depression (approximately 0.2 severity level), and lower EQ-5D-5L (-0.06, CI -0.09 to -0.03) compared to HD days. Conclusions Measuring symptom severity and EQ-5D-5L in haemodialysis populations does not need to account for dialysis schedule, but completion either on HD or non-HD days could introduce bias that may impact evaluation of interventions. Researchers should ensure completion of these instruments are standardized on either dialysis or non-dialysis days.

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Background and Aims Chronic Kidney Disease associated pruritus (CKD-aP) is common affecting 40% of people with kidney disease receiving dialysis. It is associated with decreased health-related quality of life (HRQoL) as assessed using disease-specific instruments. A better understanding of how the severity of CKD-aP is related to the distribution of affected body parts and generic of HRQoL assessed using the EQ-5D instrument could improve the identification, assessment, and treatment of CKD-aP including advocating for access to new therapies. Method Prevalent in-centre haemodialysis patients from five centres prospectively completed the EQ-5D-5L HRQoL questionnaires, the severity-based worst itch numeric rating scale (WI-NRS) and multi-dimensional 5-D itch pruritus disease specific quality of life instruments. Latent class mixture models were used to identify clusters of patients with similarly affected body parts as assessed through the 5-D itch and map the pruritus measures to the EQ-5D utility value (1 being perfect health and 0 being dead, heavily skewed). Patient demographics, comorbidities, dialysis prescription and anti-pruritus medications were collected. Results Pruritus data on 485 respondents were obtained. No pruritus was reported in 164 (33.8%), with 117 (24.1%) reporting mild, 123 (25.4%) reporting moderate and 81 (16.7%) reporting severe pruritus. Commonly affected body parts included groin (22%), upper arms (21%), forearms (11%), and back (10%). Anti-pruritus medication use across CKD-aP severity (none to severe) was 40.6%, 38.5%, 36.6% and 55.6%, and varied by body part with 38.8%, 21.0% and 14.5% use in those affected in the upper limbs, groin and lower legs respectively. Latent class analysis identified three groups of patients who had progressively worsening severity and number of body parts affected, but the distribution of affected body parts was relatively constant (left-hand figure) and reduction in EQ-5D by affected body part was similar. Although the WI-NRS and 5-D itch instruments correlated with each other, only the 5-D itch had a strong relationship with EQ-5D-3L: Controlling for age, sex, diabetes, and years receiving dialysis, predicted EQ-5D utility dropped linearly from 0.69 to 0.41 (right-hand figure). Conclusion Contemporary UK data shows CKD-aP remains highly prevalent amongst people with kidney failure on dialysis. Severe CKD-aP was commonly reported despite half of the patients with severe CKD-aP receiving antipruritic medication, illustrating a high unmet need and likely undertreated. Although there were similar reductions in HRQoL, medication use varied by body part and those whose groin is affected may be reporting other body parts to access therapies. High use of CKD-aP medications in none or mild severity may represent more severely affected individuals benefiting from these drugs as the cross-sectional nature of the study means those who reported no pruritus may have had pruritus in the past which resolved in response to the medications prescribed and reported in these analyses. Overall, as it worsens CKD-aP appears to affect a similar distribution of body parts. Pruritus instruments that include domains that are broader than just pruritus severity more closely approximate the EQ-5D generic HRQoL measure and therefore more strongly advocate for the value of treating this unpleasant condition. Funded by CSL Vifor.